Diaphragm unit, light intensity adjusting device, lens barrel, and imaging apparatus

ABSTRACT

A diaphragm unit includes: a pair of straight-moving diaphragm blades and a pair of swing diaphragm blades overlapping with each other in an optical axis direction of an optical system and forming a diaphragm opening centered on the optical axis by moving in directions in which the diaphragm blades get close to and apart from the optical axis along a plane perpendicular to the optical axis; a receiving member receiving the pair of straight-moving diaphragm blades and the pair of swing diaphragm blades; and a diaphragm driving mechanism adjusting the size of the diaphragm opening by moving the diaphragm blades. The receiving member has a pair of side surfaces facing each other in the optical axis direction. One and the other of the straight-moving diaphragm blades and one and the other of the swing diaphragm blades are disposed on one and the other of the side surfaces, respectively.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. JP 2008-322330 filed in the Japanese Patent Office on Dec. 18, 2008,the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a diaphragm unit, a light intensityadjusting device, a lens barrel, and an imaging apparatus.

2. Description of the Related Art

Portable imaging apparatuses such as moving image cameras and digitalstill cameras or projection-based optical apparatuses such as liquidcrystal projectors are provided with a light intensity adjusting device.

For example, the light intensity adjusting device includes a diaphragmunit adjusting the size of a diaphragm opening centered on an opticalaxis of an optical system and an ND filter unit reducing the lightintensity passing through the diaphragm opening.

As such a type of diaphragm unit, a diaphragm unit is known whichemploys an iris diaphragm adjusting the size of the diaphragm opening byswinging plural diaphragm blades arranged around the diaphragm openingin cooperation (see JP-A-2004-333554 (Patent Document 1)).

As such a type of ND filter unit, an ND filter unit is known in which anND filter is made to protrude to and to retreat from the diaphragmopening (see JP-A-2001-117133 (Patent Document 2)).

SUMMARY OF THE INVENTION

However, in the above-mentioned light intensity adjusting device, it isdifficult to reduce the size (thickness) in an optical axis directiondue to its structural restriction.

Accordingly, when movable lenses such as a zoom lens and a focus lensare arranged before and after the light intensity adjusting device inthe optical axis direction, the following problems are caused.

That is, when the strokes of the movable lenses are sufficientlyguaranteed, the size of a lens barrel in the optical axis directionshould be great, which is disadvantageous for a decrease in size of animaging apparatus.

When the size of the lens barrel in the optical axis direction islimited, the strokes of the movable lenses may not be sufficientlyguaranteed and thus a zoom ratio may be restricted, which isdisadvantageous for an improvement in optical performance.

Thus, it is desirable to provide a diaphragm unit, a light intensityadjusting device, a lens barrel, and an imaging apparatus, which areadvantageous for a decrease in size while guaranteeing the opticalperformance.

According to an embodiment of the invention, there is provided adiaphragm unit including: a pair of straight-moving diaphragm blades anda pair of swing diaphragm blades overlapping with each other in anoptical axis direction of an optical system and forming a diaphragmopening centered on the optical axis by moving in directions in whichthe diaphragm blades get close to and apart from the optical axis alonga plane perpendicular to the optical axis; a receiving member receivingthe pair of straight-moving diaphragm blades and the pair of swingdiaphragm blades; and a diaphragm driving mechanism adjusting the sizeof the diaphragm opening by moving the diaphragm blades. Here, thereceiving member has a pair of side surfaces facing each other in theoptical axis direction, one of the pair of straight-moving diaphragmblades and one of the pair of swing diaphragm blades are disposed on oneof the pair of side surfaces, the other of the pair of straight-movingdiaphragm blades and the other of the pair of swing diaphragm blades aredisposed on the other of the pair of side surfaces, and a concaveportion which is concave toward the other of the pair of side surfacesis disposed on one of the pair of side surfaces outside the moving locusof one of the pair of straight-moving diaphragm blades and one of thepair of swing diaphragm blades in a state where a space is secured inthe optical axis direction between the other of the pair ofstraight-moving diaphragm blades and the other of the pair of swingdiaphragm blades.

According to another embodiment of the invention, there is provided alight intensity adjusting device including: a diaphragm unit adjustingthe size of a diaphragm opening centered on an optical axis of anoptical system; and an ND filter unit reducing the light intensitypassing through the diaphragm opening. The diaphragm unit includes apair of straight-moving diaphragm blades and a pair of swing diaphragmblades overlapping with each other in the optical axis direction of theoptical system and forming the diaphragm opening centered on the opticalaxis by moving in directions in which the diaphragm blades get close toand apart from the optical axis along a plane perpendicular to theoptical axis, a diaphragm base member having a receiving sectionreceiving the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades, a diaphragm cover member covering the pair ofstraight-moving diaphragm blades and the pair of swing diaphragm bladesreceived in the receiving section, and a diaphragm driving mechanismadjusting the size of the diaphragm opening by moving the diaphragmblades. Here, one of the pair of straight-moving diaphragm blades andone of the pair of swing diaphragm blades are disposed close to thediaphragm cover member, the other of the pair of straight-movingdiaphragm blades and the other of the pair of swing diaphragm blades aredisposed close to the diaphragm base member, and a concave portion whichis concave toward the other of the pair of side surfaces is disposedclose to the diaphragm base member outside the moving locus of one ofthe pair of straight-moving diaphragm blades and one of the pair ofswing diaphragm blades in a state where a space is secured in theoptical axis direction between the other of the pair of straight-movingdiaphragm blades and the other of the pair of swing diaphragm blades.The ND filter unit includes an ND filter moving between an in-useposition located inside the diaphragm opening and a retreating positionlocated outside the diaphragm opening as viewed in the optical axisdirection, and a case receiving the ND filter. Here, the case has a sidesurface overlapping with the diaphragm cover member, a convex portionprotruding to the side surface of the diaphragm cover member andreceiving the ND filter at the retreating position is formed on the sidesurface, and the convex portion is received in the concave portion.

According to still another embodiment of the invention, there isprovided a lens barrel having a diaphragm unit, which includes: a pairof straight-moving diaphragm blades and a pair of swing diaphragm bladesoverlapping with each other in an optical axis direction of an opticalsystem and forming a diaphragm opening centered on the optical axis bymoving in directions in which the diaphragm blades get close to andapart from the optical axis along a plane perpendicular to the opticalaxis; a receiving member receiving the pair of straight-moving diaphragmblades and the pair of swing diaphragm blades; and a diaphragm drivingmechanism adjusting the size of the diaphragm opening by moving thediaphragm blades. Here, the receiving member has a pair of side surfacesfacing each other in the optical axis direction, one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades are disposed on one of the pair of side surfaces, the other ofthe pair of straight-moving diaphragm blades and the other of the pairof swing diaphragm blades are disposed on the other of the pair of sidesurfaces, and a concave portion which is concave toward the other of thepair of side surfaces is disposed on one of the pair of side surfacesoutside the moving locus of one of the pair of straight-moving diaphragmblades and one of the pair of swing diaphragm blades in a state where aspace is secured in the optical axis direction between the other of thepair of straight-moving diaphragm blades and the other of the pair ofswing diaphragm blades.

According to still another embodiment of the invention, there isprovided a lens barrel having a light intensity adjusting deviceadjusting the light intensity passing through an optical system, whereinthe light intensity adjusting device includes: a diaphragm unitadjusting the size of a diaphragm opening centered on an optical axis ofthe optical system; and an ND filter unit reducing the light intensitypassing through the diaphragm opening. The diaphragm unit includes apair of straight-moving diaphragm blades and a pair of swing diaphragmblades overlapping with each other in the optical axis direction of theoptical system and forming the diaphragm opening centered on the opticalaxis by moving in directions in which the diaphragm blades get close toand apart from the optical axis along a plane perpendicular to theoptical axis, a diaphragm base member having a receiving sectionreceiving the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades, a diaphragm cover member covering the pair ofstraight-moving diaphragm blades and the pair of swing diaphragm bladesreceived in the receiving section, and a diaphragm driving mechanismadjusting the size of the diaphragm opening by moving the diaphragmblades. Here, one of the pair of straight-moving diaphragm blades andone of the pair of swing diaphragm blades are disposed close to thediaphragm cover member, the other of the pair of straight-movingdiaphragm blades and the other of the pair of swing diaphragm blades aredisposed close to the diaphragm base member, and a concave portion whichis concave toward the other of the pair of side surfaces is disposedclose to the diaphragm base member outside the moving locus of one ofthe pair of straight-moving diaphragm blades and one of the pair ofswing diaphragm blades in a state where a space is secured in theoptical axis direction between the other of the pair of straight-movingdiaphragm blades and the other of the pair of swing diaphragm blades.The ND filter unit includes an ND filter moving between an in-useposition located inside the diaphragm opening and a retreating positionlocated outside the diaphragm opening as viewed in the optical axisdirection, and a case receiving the ND filter. Here, the case has a sidesurface overlapping with the diaphragm cover member, a convex portionprotruding to the side surface of the diaphragm cover member andreceiving the ND filter at the retreating position is formed on the sidesurface, and the convex portion is received in the concave portion.

According to yet another embodiment of the invention, there is providedan imaging apparatus having a lens barrel mounted with a diaphragm unitwhich includes: a pair of straight-moving diaphragm blades and a pair ofswing diaphragm blades overlapping with each other in an optical axisdirection of an optical system and forming a diaphragm opening centeredon the optical axis by moving in directions in which the diaphragmblades get close to and apart from the optical axis along a planeperpendicular to the optical axis; a receiving member receiving the pairof straight-moving diaphragm blades and the pair of swing diaphragmblades; and a diaphragm driving mechanism adjusting the size of thediaphragm opening by moving the diaphragm blades. Here, the receivingmember has a pair of side surfaces facing each other in the optical axisdirection, one of the pair of straight-moving diaphragm blades and oneof the pair of swing diaphragm blades are disposed on one of the pair ofside surfaces, the other of the pair of straight-moving diaphragm bladesand the other of the pair of swing diaphragm blades are disposed on theother of the pair of side surfaces, and a concave portion which isconcave toward the other of the pair of side surfaces is disposed on oneof the pair of side surfaces outside the moving locus of one of the pairof straight-moving diaphragm blades and one of the pair of swingdiaphragm blades in a state where a space is secured in the optical axisdirection between the other of the pair of straight-moving diaphragmblades and the other of the pair of swing diaphragm blades.

According to further another embodiment of the invention, there isprovided an imaging apparatus having a lens barrel mounted with a lightintensity adjusting device, wherein the light intensity adjusting deviceincludes: a diaphragm unit adjusting the size of a diaphragm openingcentered on an optical axis of the optical system; and an ND filter unitreducing the light intensity passing through the diaphragm opening. Thediaphragm unit includes a pair of straight-moving diaphragm blades and apair of swing diaphragm blades overlapping with each other in theoptical axis direction of the optical system and forming the diaphragmopening centered on the optical axis by moving in directions in whichthe diaphragm blades get close to and apart from the optical axis alonga plane perpendicular to the optical axis, a diaphragm base memberhaving a receiving section receiving the pair of straight-movingdiaphragm blades and the pair of swing diaphragm blades, a diaphragmcover member covering the pair of straight-moving diaphragm blades andthe pair of swing diaphragm blades received in the receiving section,and a diaphragm driving mechanism adjusting the size of the diaphragmopening by moving the diaphragm blades. Here, one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades are disposed close to the diaphragm cover member, the other ofthe pair of straight-moving diaphragm blades and the other of the pairof swing diaphragm blades are disposed close to the diaphragm basemember, and a concave portion which is concave toward the other of thepair of side surfaces is disposed close to the diaphragm base memberoutside the moving locus of one of the pair of straight-moving diaphragmblades and one of the pair of swing diaphragm blades in a state where aspace is secured in the optical axis direction between the other of thepair of straight-moving diaphragm blades and the other of the pair ofswing diaphragm blades. The ND filter unit includes an ND filter movingbetween an in-use position located inside the diaphragm opening and aretreating position located outside the diaphragm opening as viewed inthe optical axis direction, and a case receiving the ND filter. Here,the case has a side surface overlapping with the diaphragm cover member,a convex portion protruding to the side surface of the diaphragm covermember and receiving the ND filter at the retreating position is formedon the side surface, and the convex portion is received in the concaveportion.

According to the above-mentioned embodiments of the invention, since theconcave portion is disposed in one side surface of the receiving memberreceiving the diaphragm unit, it is possible to reduce the size of thelens barrel in the optical axis direction by receiving and arranginganother optical device or a part thereof, or an optical member or a partthereof in the concave portion. Therefore, it is advantageous for thedecrease in size of the imaging apparatus.

Alternatively, it is possible to guarantee the strokes of the movablelenses such as a zoom lens and a focus lens great without an increase inlength of the lens barrel. Therefore, it is possible to guarantee thezoom ratio and to guarantee a focus adjusting range great, which isadvantageous for the improvement in optical performance of the lensbarrel.

Since an inexpensive lens with a relatively small refractive index and alarge thickness can be used as the movable lens, it is advantageous forthe decrease in cost of the imaging apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an imaging apparatus according to anembodiment of the invention.

FIG. 2 is a perspective view illustrating a state where a display panelof the imaging apparatus is located at an open position.

FIG. 3 is a block diagram illustrating the configuration of a controlsystem of the imaging apparatus.

FIG. 4 is an exploded perspective view of a diaphragm unit as viewedfrom the front side.

FIG. 5 is an exploded perspective view of the diaphragm unit as viewedfrom the rear side.

FIG. 6 is a diagram illustrating the attachment of a diaphragm motor toa diaphragm base member.

FIG. 7 is a plan view illustrating a state where the diaphragm motor andan annular plate are attached to the diaphragm base member.

FIG. 8 is a diagram illustrating the attachment of the annular plate, afixed diaphragm, and a partition plate to the diaphragm base member.

FIG. 9 is an exploded perspective view illustrating the partition plate,a diaphragm cover member, diaphragm blades, and spacers.

FIG. 10 is a perspective view of the partition plate as viewed from therear side.

FIG. 11 is a perspective view of the diaphragm cover member as viewedfrom the front side.

FIG. 12 is a plan view of the diaphragm unit where a diaphragm openingis open as viewed from the rear side.

FIG. 13 is a plan view of the diaphragm unit where the diaphragm openingis narrowed by one step as viewed from the rear side.

FIG. 14 is a plan view of the diaphragm unit where the diaphragm openingis narrowed by six steps as viewed from the rear side.

FIG. 15 is a plan view of the diaphragm unit as viewed from the rearside when the diaphragm opening is completely closed.

FIG. 16 is a plan view illustrating the position of one second swingdiaphragm blade when the diaphragm opening is open.

FIG. 17 is a plan view illustrating the position of one second swingdiaphragm blade when the diaphragm opening is completely closed.

FIG. 18 is a plan view illustrating the positions of one straight-movingdiaphragm blade, one first swing diaphragm blade, and one second swingdiaphragm blade when the diaphragm opening is open.

FIG. 19 is a plan view illustrating the positions of one straight-movingdiaphragm blade, one first swing diaphragm blade, and one second swingdiaphragm blade when the diaphragm opening is completely closed.

FIG. 20 is a sectional view illustrating the partition plate, onestraight-moving diaphragm blade, one first swing diaphragm blade, andone second swing diaphragm blade.

FIG. 21 is a plan view of the straight-moving diaphragm blade.

FIG. 22 is a plan view of the first swing diaphragm blade.

FIG. 23 is a plan view of the second swing diaphragm blade.

FIG. 24 is a plan view of the spacer.

FIG. 25 is an enlarged view illustrating the vicinity of the spacer.

FIG. 26 is an enlarged view where the spacer is removed from FIG. 25.

FIG. 27 is an exploded perspective view of a light intensity adjustingdevice.

FIG. 28 is a perspective view of the light intensity adjusting device asviewed from the front side.

FIG. 29 is an exploded perspective view of an ND filter unit.

FIG. 30 is a perspective view of a filter support member to which an NDfilter is attached.

FIG. 31 is a perspective view of the diaphragm unit from which adiaphragm cover member is detached as viewed from the rear side.

FIG. 32 is a perspective view of the diaphragm unit to which thediaphragm cover member is attached as viewed from the rear side.

FIG. 33 is a perspective view illustrating a state where a filter covermember is attached to the diaphragm unit.

FIG. 34 is a perspective view illustrating a state where the ND filterand the filter support member are attached to the assembly shown in FIG.33.

FIG. 35 is a sectional view taken along line AA of FIG. 34 where aretreating position of the ND filter is shown.

FIG. 36 is a sectional view taken along line AA of FIG. 34 where anin-use position of the ND filter is shown.

FIG. 37 is a sectional view of the light intensity adjusting devicewhere the retreating position of the ND filter is shown.

FIG. 38 is a sectional view of a light intensity adjusting deviceaccording to a second embodiment of the invention.

FIG. 39 is a sectional view of a diaphragm unit according to ComparativeExample 1.

FIG. 40 is a sectional view of a diaphragm unit according to ComparativeExample 2.

FIG. 41 is a plan view of diaphragm blades according to ComparativeExample 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Hereinafter, an embodiment of the invention will be described withreference to the accompanying drawings.

FIG. 1 is a perspective view of an imaging apparatus 10 according to anembodiment of the invention. FIG. 2 is a perspective view illustrating astate where a display panel 22 of the imaging apparatus 10 is located atan open position. FIG. 3 is a block diagram illustrating theconfiguration of a control system of the imaging apparatus 10.

The configuration of a control system of an imaging apparatus 10 will bedescribed now with reference to FIG. 3.

In this embodiment, the imaging apparatus 10 is a moving image cameraand serves to record data of taken moving images, still images, andsounds in a recording medium and to reproduce the data from therecording medium.

In this embodiment, a memory card 2 which is a plate-like or rod-likerecording medium is used as the recording medium. However, a magneticrecording tape, an optical disk, a hard disk may be used as therecording medium, and the recording medium is not particularly limited.

The imaging apparatus 10 has a chassis 12 forming the outer shape and alens barrel 16 mounted with a photographing optical system 14 isdisposed in the chassis 12.

The rear end of the lens barrel 16 is provided with an imaging device 18imaging a subject image guided by the photographing optical system 14.The lens barrel 16 is mounted with a light intensity adjusting device 39to be described later. The light intensity adjusting device 39 serves toadjust the light intensity passing through the photographing opticalsystem 14. The light intensity adjusting device 39 includes a diaphragmunit 40 and an ND filter unit 41.

The imaging apparatus 10 includes a microphone 20, a display panel 22, aspeaker 26, an image signal amplifier 102, an image signal processor104, a microphone amplifier 106, an audio signal processor 108, anoutput amplifier 110, a recording and reproducing unit 112, and acontroller 114.

The imaging apparatus 10 further includes a display panel driver 116, abuffer memory 118, a memory card interface 120, an operation unit 126,an external input and output interface 128, an external input and outputterminal 130, and a motor driver 43.

An imaging signal generated from the imaging device 18 is amplified bythe image signal amplifier 102 and is then supplied to the image signalprocessor 104.

The image signal processor 104 performs a predetermined signal processon the imaging signal to generate moving image data and still image dataand supplies the generated data to the recording and reproducing unit112.

An audio signal received by the microphone 20 is amplified by themicrophone amplifier 106, is subjected to a predetermined signal processby the audio signal processor 108, and is then supplied as audio data tothe recording and reproducing unit 112.

The recording and reproducing unit 112 records the moving image data andthe still image data supplied from the image signal processor 104 andthe audio data supplied from the audio signal processor 108 on a memorycard 2 via the memory card interface 120 under the control of thecontroller 114.

The recording of data in the memory card 2 by the recording andreproducing unit 112 is carried out, for example, by temporarily storingthe data to be recorded in the memory card 2 in the buffer memory 118and then writing the data read from the buffer memory 118 to the memorycard 2.

The recording and reproducing unit 112 supplies the moving image dataand the still image data supplied from the image signal processor 104 tothe display panel 22 via the display panel driver 116 so as to displayan image.

The recording and reproducing unit 112 supplies the moving image dataand the still image data, which are supplied from the memory card 2 viathe memory card interface 120, to the display panel 22 via the displaypanel driver 116 so as to display an image.

The recording and reproducing unit 112 supplies the audio signal, whichis supplied from the memory card 2 via the memory card interface 120, tothe speaker 26 via the output amplifier 110 so as to output a sound.

The external input and output interface 128 serves to convert the audiodata and the image data reproduced by the recording and reproducing unit112 into a predetermined signal format and to output the converted datato an external device such as a television set, an HDD recorder, and apersonal computer via the external input and output terminal 130.

The operation unit 126 includes plural operation switches 24, a powerswitch 28A, a still image photographing switch 28B, a zoom switch 28C, amode switching switch 28D, and a moving image photographing switch 28Eas shown in FIG. 2.

The switches 24 and 28A to 28E constitute operation switches forcarrying out various functions relating to the photographing operation.

The controller 114 turns on and off the imaging apparatus 10 on thebasis of the operation on the power switch 28A.

The controller 114 gives an instruction to the image signal processor104 and the recording and reproducing unit 112 on the basis of theoperation on the still image photographing switch 28B. Accordingly, thecontroller 114 records the still image data in the memory card 2 bysupplying the still image data supplied from the image signal processor104 to the memory card interface 120 via the recording and reproducingunit 112.

In other words, the still image photographing switch 28B serves as aso-called shutter button.

The controller 114 changes the zoom ratio of the photographing opticalsystem 14 by giving an instruction to a zoom driver (not shown) on thebasis of the operation on the zoom switch 28C to cause the movable lensof the photographing optical system 14 to move.

The controller 114 gives an instruction to the image signal processor104 on the basis of the operation on the mode switching switch 28D.Accordingly, the controller 114 switches the operation mode between avideo photographing mode for allowing the image signal processor 104 togenerate the moving image data and a still image photographing mode forallowing the image signal processor 104 to generate the still imagedata.

In the moving image photographing mode, the moving image data generatedby the image signal processor 104 is recorded in the memory card 2 bythe recording and reproducing unit 112. In the still image photographingmode, the still image data generated by the image signal processor 104is recorded in the memory card 2 by the recording and reproducing unit112.

The controller 114 starts or stops recording the moving image data onthe basis of the operation on the moving image photographing switch 28E.

That is, the controller 114 gives an instruction to the image signalprocessor 104 and the recording and reproducing unit 112 on the basis ofthe operation on the moving image photographing switch 28E. Accordingly,the controller 114 supplies the moving image data supplied from theimage signal processor 104 to the memory card interface 120 via therecording and reproducing unit 112. As a result, the controller 114starts or stops the operation of recording the moving image data in thememory card 2.

In other words, the moving image photographing switch 28E serves as aso-called photographing start and stop operation member.

A panel-side moving image photographing switch 30A, a panel-side zoomswitch 30B, and a menu operating switch 30C are connected to thecontroller 114.

The panel-side moving image photographing switch 30A has the samefunction as the moving image photographing switch 28E.

The panel-side zoom switch 30B has the same function as the zoom switch28C.

The menu operating switch 30C is a switch operated to directly return alayer of the menu displayed on the display panel 22 to the uppermostlayer.

The motor driver 43 controls the driving of a diaphragm motor 56 (seeFIG. 4) of the diaphragm unit 40 and a filter motor 84 of the ND filterunit 41, which are all described later, under the control of thecontroller 114.

The configuration of the imaging apparatus 10 will be described now.

As shown in FIGS. 1 and 2, the chassis 12 has a length in the front andrear directions and a height in the up-down directions greater than thewidth in the left-right directions. In this specification, the left andright sides are determined when the imaging apparatus 10 is viewed fromthe rear side. The side close to a subject in the optical axis directionof the optical system is called front and the side close to the imagingdevice is called rear.

The lens barrel 16 extends from the front to the rear in the upper sideof the chassis 12 and the front part thereof is located on the frontsurface of the chassis 12. Accordingly, the subject image is guided fromthe front part of the chassis 12 to the inside of the chassis 12.

The imaging device 18 (FIG. 3) is disposed at the rear end of the lensbarrel 16.

The microphone 20 is disposed on the top surface of the lens barrel 16.

The display panel 22 is disposed on the left side of the chassis 12 soas to be opened and closed.

The display panel 22 includes a display device 32 and a panel case 34and has a rectangular plate shape.

As shown in FIG. 2, the display device 32 serves to display the subjectimage imaged by the imaging device 18.

The display device 32 includes a rectangular display surface 3202 onwhich an image is displayed and the display surface 3202 forms the innersurface of the display panel 22.

In this embodiment, the display device 32 is formed of a liquid crystaldisplay device, but the type of the display device 32 is notparticularly limited and for example, may be an organic EL displaydevice.

The short-side part of the display panel 22 is connected to the frontposition of the left-side part of the chassis 12 with a hinge 2202interposed therebetween.

Accordingly, the display panel 22 can swing about a first axis line O1extending in the up-down directions of the chassis 12 and can also swingabout a second axis line O2 perpendicular to the first axis line O1.

In this embodiment, the display panel 22 swings between a receivingposition shown in FIG. 1 and an open position shown in FIG. 2.

That is, at the receiving position shown in FIG. 1, the display surface3202 (the inner surface of the panel 22) of the display device 32 of thedisplay panel 22 is located to overlap with the left surface 12A of thechassis 12 around the first axis line O1.

At the open position shown in FIG. 2, the display panel 22 is openedfrom the receiving position by 90 degrees and the display surface 3202of the display device 32 faces the rear side.

At the receiving position where the display surface 3202 (the innersurface of the panel 22) overlaps with the left surface 12A of thechassis 12, the outer surface 2210 of the display panel 22 (see FIG. 1)faces the outside.

At the open position, the display panel 22 swings about the second axisline O2 between a position where the display surface 3202 of the displaydevice 32 faces the front side and a position where the display surfacefaces the down side in a range of 270 degrees.

As shown in FIG. 2, plural operation switches 24 for performing variousoperations, the speaker 26, and the like are disposed on the leftsurface 12A of the chassis 12.

The power switch 28A, the still image photographing switch 28B, the zoomswitch 28C, and the mode switching switch 28D are disposed close to therear end of the upper part of the chassis 12. The moving imagephotographing switch 28E is disposed on the rear surface of the chassis12.

The display panel 22 is provided with the panel-side moving imagephotographing switch 30A, the panel-side zoom switch 30B, and the menuoperating switch 30C.

As shown in FIG. 2, a slot 36 into and from which a memory card 2 isinserted and detached and a cover member 38 covering an opening 3602 ofthe slot 36 are disposed in the lower part of the left surface 12A ofthe chassis 12.

By inserting the memory card 2 into the slot 36, a connection terminalof the memory card 2 is electrically connected to a connector (notshown) in the slot 36. Accordingly, the memory card 2 transmits andreceives data to and from the memory card interface 120 via theconnector.

The light intensity adjusting apparatus 39 includes a diaphragm unit 40and an ND filter unit 41. The diaphragm unit 40 and the ND filter unit41 are mounted on a lens barrel.

The diaphragm unit 40 will be described now with reference to FIGS. 4 to26.

FIG. 4 is an exploded perspective view of the diaphragm unit 40 asviewed from the front side. FIG. 5 is an exploded perspective view ofthe diaphragm unit 40 as viewed from the rear side.

FIG. 6 is a diagram illustrating the attachment of a diaphragm motor 56to a diaphragm base member 42. FIG. 7 is a plan view illustrating astate where the diaphragm motor 56 and the annular plate 54 are attachedto the diaphragm base member 42.

FIG. 8 is a diagram illustrating the attachment of the annular plate 54,a fixed diaphragm 70, and the partition plate 44 to the diaphragm basemember 42. FIG. 9 is an exploded perspective view illustrating thepartition plate 44, the diaphragm cover member 58, diaphragm blades 46,48, and 50, and spacers 52.

FIG. 10 is a perspective view of the partition plate as viewed from therear side. FIG. 11 is a perspective view of the diaphragm cover member58 as viewed from the front side.

FIG. 12 is a plan view of the diaphragm unit 40 where the diaphragmopening 2 is open as viewed from the rear side.

FIG. 13 is a plan view of the diaphragm unit 40 where the diaphragmopening 2 is narrowed by one step as viewed from the rear side.

FIG. 14 is a plan view of the diaphragm unit 40 where the diaphragmopening 2 is narrowed by six steps as viewed from the rear side.

FIG. 15 is a plan view of the diaphragm unit 40 as viewed from the rearside when the diaphragm opening 2 is completely closed.

As shown in FIGS. 3 and 12, the diaphragm unit 40 serves to adjust thelight intensity guided to the imaging device 18 by adjusting the size ofthe diaphragm opening 2 for limiting the beam of light guided to theimaging device 18 via the photographing optical system 14.

The diaphragm unit 40 is disposed in front of the imaging device 18.

In this embodiment, the diaphragm unit 40 includes a diaphragm basemember 42, a partition plate 44, a pair of straight-moving diaphragmblades 46, a pair of first swing diaphragm blades 48, a pair of secondswing diaphragm blades 50, two spacers 52, an annular plate 54, adiaphragm motor 56, and a diaphragm cover member 58.

In this embodiment, a receiving member receiving the pair ofstraight-moving diaphragm blades 46, the pair of first swing diaphragmblades 48, and the pair of second swing diaphragm blades 50 isconstructed by the diaphragm base member 42 and the diaphragm covermember 58.

The diaphragm base member 42 is formed in a rectangular plate shape outof a synthetic resin not transmitting light and is attached to the lensbarrel 16 in a state where the longitudinal side is parallel to theup-down side of the chassis 12.

As shown in FIGS. 4 and 5, the diaphragm base member 42 has a frontsurface 42A facing the front side and a rear surface 42B facing the rearside. A circular optical path hole 42C centered on the optical axis L ofthe photographing optical system 14 is formed in the diaphragm basemember 42.

As shown in FIG. 5, a receiving section 60 having a concave shape toreceive the partition plate 44, the pair of straight-moving diaphragmblades 46, the pair of first swing diaphragm blades 48, the pair ofsecond swing diaphragm blades 50, two spacers 52, and the annular plate54 are formed in the rear surface 42B of the diaphragm base member 42.

As shown in FIG. 7, two straight-moving diaphragm blade guide pins 62slidably guiding two straight-moving diaphragm blades 46 are disposed inthe rear surface 42B for each straight-moving diaphragm blade 46. Thestraight-moving diaphragm blade guide pins 62 are arranged around theoptical path hole 42C.

As shown in FIG. 7, first swing diaphragm blade spindles 64 supportingthe pair of first swing diaphragm blades 48 so as to be capable ofswinging are disposed in the rear surface 42B. Second swing diaphragmblade spindles 66 supporting the pair of second swing diaphragm blades50 so as to be capable of swinging are disposed in the rear surface 42B.

As shown in FIG. 6, a circular concave portion 68 receiving the annularplate 54 and rotatably supporting the annular plate 54 are formed aroundthe optical path hole 42C at the bottom of the concave receiving section60.

In the concave portion 68, as shown in FIGS. 7 and 8, fan-like concaveportions 68A and 68B allowing the protrusion 54C and the gear portion 55of the annular plate 54 to move as described later protrude to theoutside in the radial direction of the concave portion 68 and extendsaround the concave portion 68.

As shown in FIGS. 5 and 7, the annular plate 54 has a ring-like annularplate portion 54A formed of a synthetic resin not transmitting light andan optical path hole 54B is formed at the center of the annular plateportion 54A.

The protrusion 54C is disposed in a part of the circumference of theannular plate portion 54A.

The gear portion 55 is disposed at the position of the circumference ofthe annular plate portion 54A separated from the protrusion 54C by 180degrees. The gear portion 55 has a fan shape centered on the center axisof the annular plate 54.

Two straight-moving diaphragm blade driving pins 54D and two first swingdiaphragm blade driving pins 54E are disposed on the surface (facing therear side) of the annular plate portion 54A facing the other side in thethickness direction.

A second swing diaphragm blade driving pin 54F is formed to protrudefrom each of the surface (the surface facing the rear side) where theprotrusion 54C faces the other side in the thickness direction and thesurface (the surface facing the rear side) where the gear portion 55faces the other side in the thickness direction.

Two straight-moving diaphragm blade driving pins 54D are disposed with agap of 180 degrees about the center axis of the annular plate 54.

Two first swing diaphragm blade driving pins 54E are disposed with a gapof 180 degrees about the center axis of the annular plate 54.

Two second swing diaphragm blade driving pins 54F are disposed with agap of 180 degrees about the center axis of the annular plate 54.

As shown in FIG. 6, the diaphragm motor 56 includes a case 56A, anattachment piece 56B, and a driving gear 56C.

The driving gear 56C is rotationally driven forwardly and backwardly onthe basis of the driving current supplied from the motor driver 43 (seeFIG. 3).

The case 56A is attached to the front surface 42A of the base member 42with the attachment piece 56B interposed therebetween.

The driving gear 56C is fixed to a driving shaft protruding from one endof the case 56A.

As shown in FIG. 7, the driving gear 56C engages with the gear portion55 of the annular plate 54 on the rear surface 42B of the base member 42through an opening 4202 of the base member 42.

By rotationally driving the diaphragm motor 56 forwardly and backwardly,the annular plate 54 swings in the clockwise direction and thecounterclockwise direction about the center axis of the annular plate 54via the driving gear 56C and the gear portion 55.

In FIG. 5, reference numeral 70 represents a fixed diaphragm disposedbetween the annular plate 54 and the partition plate 44.

The fixed diaphragm 70 is formed in a thin plate shape out of asynthetic resin not transmitting light.

As shown in FIG. 8, a circular hole 70A for determining the maximumdiameter of the diaphragm opening 2 is formed at the center of the fixeddiaphragm 70.

Two relief grooves 70B into which two straight-moving diaphragm bladedriving pins 54D and two first swing diaphragm blade driving pins 54Eare inserted are disposed in the fixed diaphragm 70 so as to extend inthe circumferential direction of the optical axis L.

Insertion holes 70C into which four straight-moving diaphragm bladeguide pins 62 are inserted are formed in the fixed diaphragm 70.

By inserting the straight-moving diaphragm blade guide pins 62 into theinsertion holes 70C, the fixed diaphragm 70 is not movable in the planeperpendicular to the optical axis L.

As shown in FIGS. 4 and 5, the partition plate 44 is interposed betweenthe annular plate 54 and plural diaphragm blades 46, 48, and 50 andserves to separate the annular plate 54 from the plural diaphragm blades46, 48, and 50.

The partition plate 44 is formed of a rectangular steel sheet and has anoptical path hole 44A formed therein so as to expose the diaphragmopening 2 in the direction of the optical axis L in the sate where it isattached to the diaphragm base member 42.

The optical path hole 44A has a diameter equal to or greater than thehole 70A of the fixed diaphragm 70.

As shown in FIGS. 5 and 10, a first insertion portion 4402, a secondinsertion portion 4404, a first rail 4410, a second rail 4412, a thirdrail 4414, a fourth rail 4416, and a fifth rail 4418 are formed in thepartition plate 44.

Two straight-moving diaphragm blade driving pins 54D and two first swingdiaphragm blade driving pins 54E are loosely inserted into the firstinsertion portion 4402 and two first insertion portions are formed toextend in the circumferential direction of the optical axis L. Twostraight-moving diaphragm blade driving pins 54D and two first swingdiaphragm blade driving pins 54E swing in the first insertion portions4402 without interfering with the partition plate 44.

Two second swing diaphragm blade driving pins 54F are loosely insertedinto the second insertion portion 4404 and two second insertion portionsare formed to extend in the circumferential direction of the opticalaxis L. Two second swing diaphragm blade driving pins 54F swing in thesecond insertion portions 4404 without interfering with the partitionplate 44.

The first rail 4410 serves to guide the movement of the straight-movingdiaphragm blade 46 disposed close to the partition plate 44 out of thepair of straight-moving diaphragm blades 46. In this embodiment, fourfirst rails are disposed to linearly extend in the moving direction (inthe up-down directions) of the straight-moving diaphragm blade 46.

The second rail 4412 serves to guide the movement of the second swingdiaphragm blade 50 disposed close to the partition plate 44 out of thepair of second swing diaphragm blades 50. In this embodiment, two secondrails are disposed to extend arc-like in the moving direction of thesecond swing diaphragm blade 50.

The third rail 4414 serves to guide the movement of the straight-movingdiaphragm blade 46 disposed close to the diaphragm cover member 58 outof the pair of straight-moving diaphragm blades 46. In this embodiment,three third rails are disposed to linearly extend in the movingdirection of the straight-moving diaphragm blade 46.

The fourth rail 4416 comes in contact with the spacer 52 disposed on oneside in the width direction of the partition plate 44 out of the pair ofspacers 52. In this embodiment, two fourth rails 4416 are disposed tolinearly extend in the moving direction (in the up-down directions) ofthe spacer 52.

The fifth rail 4418 comes in contact with the spacer 52 disposed on theother side in the width direction of the partition plate 44 out of thepair of spacers 52. In this embodiment, one fifth rail 4418 is disposedto linearly extend in the moving direction (in the up-down directions)of the spacer 52.

In FIG. 10, reference numeral 4420 represents cutouts which are formedin the partition plate 44 and into which four straight-moving diaphragmblade guide pins 62 are loosely inserted.

Reference numeral 4422 represents insertion holes which are formed inthe partition plate 44 and into which two first swing diaphragm bladespindles 64 are inserted.

Reference numeral 4424 represents insertion holes which are formed inthe partition plate 44 and into which two second swing diaphragm bladespindles 66 are inserted.

By inserting two first swing diaphragm blade spindles 64 and two secondswing diaphragm blade spindles 66 into the insertion holes 4422 and4424, the partition plate 44 is not capable of moving in the planeperpendicular to the optical axis L.

Reference numeral 4426 represents engagement claws which are formed inthe partition plate 44 and which allows the partition plate 44 to engagewith the diaphragm base member 42. In this embodiment, one engagementclaw 4426 is disposed on one (upper) edge in the longitudinal directionof the partition plate 44 and two engagement claws are disposed on theother (lower) edge.

FIG. 21 is a plan view of the straight-moving diaphragm blade 46.

The straight-moving diaphragm blade 46 is formed in a thin plate shapeout of a synthetic resin not transmitting light and includes a linearportion and a curved portion extending continuously from the linearportion.

Two linear guide grooves 4602 and a cam groove 4604 are formed in thelinear portion and an opening forming edge portion 46A is formed in thecurved portion.

Two linear guide grooves 4602 serve to straight-movably guide thestraight-moving diaphragm blade 46 and extends in the straight linealong the linear portion.

The cam groove 4604 extends in the direction perpendicular to thestraight line between two linear guide grooves 4062.

The opening forming edge portion 46A serves to form the diaphragmopening 2 of the diaphragm unit 40 and extends in a semi-circularconcave shape along the curved portion.

FIG. 22 is a plan view of the first swing diaphragm blade 48.

The first swing diaphragm blade 48 is formed in a thin plate shape outof a synthetic resin not transmitting light and has a longitudinalshape.

The first swing diaphragm blade 48 is provided with a hole 4802, a camgroove 4804, and an opening forming edge portion 48A.

The hole 4802 is formed at one end in the longitudinal direction of thefirst swing diaphragm blade 48.

The cam groove 4804 extends in the middle portion in the longitudinaldirection of the first swing diaphragm blade 48.

The opening forming edge portion 48A serves to form the diaphragmopening 2 of the diaphragm unit 40 and extends in a circular arc-likeconcave shape along one side of the width direction of the other end inthe longitudinal direction of the first swing diaphragm blade 48.

FIG. 23 is a plan view of the second swing diaphragm blade 50.

The second swing diaphragm blade 50 is formed in a thin plate shape outof a synthetic resin not transmitting light and has a shape of which thewidth decreases as it approaches to both ends in the longitudinaldirection.

The second swing diaphragm blade 50 is provided with a hole 5002, a camgroove 5004, and an opening forming edge portion 50A.

The hole 5002 is formed at one end in the longitudinal direction of thesecond swing diaphragm blade.

The cam groove 5004 extends in the middle portion in the longitudinaldirection.

The opening forming edge portion 50A serves to form the diaphragmopening 2 of the diaphragm unit 40 and extends in a circular concaveshape along one side in the width direction of the other end in thelongitudinal direction of the second swing diaphragm blade 50.

FIG. 24 is a plan view of the spacer 52.

The spacer 52 is formed in a thin plate shape out of a synthetic resinnot transmitting light and has a longitudinal shape.

Two attachment holes 5202 are formed in the spacer 52 with a gap in thelongitudinal direction.

The diaphragm cover member 58 is attached to the diaphragm base member42 so as to cover the plural diaphragm blades 46, 48, and 50, thespacers 52, the fixed diaphragm 70, and the annular plate 54, which arereceived in the receiving section 60, and holds the members such thatthey do not drop from the diaphragm base member 42.

The diaphragm cover member 58 is formed of a rectangular thin steelplate.

An optical path hole 58A is formed in the diaphragm cover member 58 soas to expose the diaphragm opening 2 in the direction of the opticalaxis L in the state where it is attached to the diaphragm base member42.

The optical path hole 58A has a diameter equal to or greater than thehole 70A of the fixed diaphragm 70.

As shown in FIGS. 5 and 11, a third insertion portion 5802, a fourthinsertion portion 5804, a sixth rail 5810, a seventh rail 5812, aneighth rail 5814, a ninth rail 5816, and a tenth rail 5818 are formed inthe diaphragm cover member 58.

Two straight-moving diaphragm blade driving pins 54D and two first swingdiaphragm blade driving pins 54E are loosely inserted into the thirdinsertion portion 5802. Two third insertion portions are formed toextend in the circumferential direction of the optical axis L.

Two second swing diaphragm blade driving pins 54F are loosely insertedinto the fourth insertion portion 5804.

Two insertion portions are formed to extend in the circumferentialdirection of the optical axis.

The sixth rail 5810 serves to guide the movement of the straight-movingdiaphragm blade 46 disposed close to the diaphragm cover member 58 outof the pair of straight-moving diaphragm blades 46. In this embodiment,four sixth rails are formed to linearly extend in the moving direction(in the up-down directions) of the straight-moving diaphragm blade 46.

The seventh rail 5812 serves to guide the movement of the second swingdiaphragm blade 50 disposed close to the diaphragm cover member 58 outof the pair of second swing diaphragm blades 50. In this embodiment, twoseventh rails are formed to linearly extend in the moving direction ofthe second swing diaphragm blade 50.

The eighth rail 5814 serves to guide the movement of the straight-movingdiaphragm blade 46 disposed close to the partition plate 44 out of thepair of straight-moving diaphragm blades 46. In this embodiment, threeeighth rails are formed to linearly extend in the moving direction (inthe up-down directions) of the straight-moving diaphragm blade 46.

The ninth rail 5816 comes in contact with the spacer disposed on oneside in the width direction of the partition plate 44 out of the pairspacers 52. In this embodiment, one ninth rail 5816 is disposed toextend linearly in the extending direction (in the up-down directions)of the spacer 52.

The tenth rail 5818 comes in contact with the spacer 52 disposed on theother side in the width direction of the partition plate 44 out of thepair spacers 52. In this embodiment, two tenth rails 5818 are disposedto linearly extend in the extending direction (in the up-downdirections) of the spacer 52.

Therefore, in this embodiment, the spacer 52 disposed on one side in thewidth direction of the partition plate 44 is interposed in the directionof the optical axis L between the fourth rail 4416 and the ninth rail5816 and is thus positioned in the direction of the optical axis L.

In this embodiment, the spacer 52 disposed on the other side in thewidth direction of the partition plate 44 is interposed in the directionof the optical axis L between the fifth rail 4418 and the tenth rail5818 and is thus positioned in the direction of the optical axis L.

In FIG. 11, reference numeral 5820 represents insertion holes into whichfour straight-moving diaphragm blade guide pins 62 are inserted.

Reference numeral 5822 represents insertion holes which are formed inthe diaphragm cover member 58 and into which two first swing diaphragmblade spindles 64 are inserted.

Reference numeral 5824 represents insertion holes which are formed inthe diaphragm cover member 58 and into which two second swing diaphragmblade spindles 66 are inserted.

By inserting two first swing diaphragm blade spindles 64 and two secondswing diaphragm blade spindles 66 into the insertion holes 5822 and5824, the diaphragm cover member 58 is not capable of moving in theplane perpendicular to the optical axis L.

Reference numeral 5826 represents engagement claws which are formed inthe diaphragm cover member 58 and which allows the diaphragm covermember 58 to engage with the diaphragm base member 42. In thisembodiment, two engagement claws 5826 are disposed on one (upper) edgein the longitudinal direction of the diaphragm cover member 58 and oneengagement claw 5826 is disposed on the other (lower) edge.

As described later, one of the pair of straight-moving diaphragm blades46, one of the pair of first swing diaphragm blades 48, and one of thepair of second swing diaphragm blades 50 are disposed close to thediaphragm cover member 58.

The other of the pair of straight-moving diaphragm blades 46, the otherof the pair of first swing diaphragm blades 48, and the other of thepair of second swing diaphragm blades 50 are disposed close to thediaphragm base member 42.

One of the pair of straight-moving diaphragm blades 46, one of the pairof first swing diaphragm blades 48, and one of the pair of second swingdiaphragm blades 50 move almost in the upper half area of the diaphragmunit 40.

The other of the pair of straight-moving diaphragm blades 46, the otherof the pair of first swing diaphragm blades 48, and the other of thepair of second swing diaphragm blades 50 move almost in the lower halfarea of the diaphragm unit 40.

That is, when the diaphragm unit 40 is divided into two areas by the useof a virtual line perpendicular to the optical axis L, one of the pairof straight-moving diaphragm blades 46, one of the pair of first swingdiaphragm blades 48, and one of the pair of second swing diaphragmblades 50 move almost in one area of two divided areas.

When the diaphragm unit 40 is divided into two areas by the use of avirtual line perpendicular to the optical axis L, the other of the pairof straight-moving diaphragm blades 46, the other of the pair of firstswing diaphragm blades 48, and the other of the pair of second swingdiaphragm blades 50 move almost in the other area of two divided areas.

The diaphragm cover member 58 is provided with a concave portion 5850(see FIGS. 32 and 35) which is concave toward the diaphragm base member42.

The diaphragm cover member 58 disposed in the concave portion 5850 islocated outside the moving locus of one of the pair of straight-movingdiaphragm blades 46, one of the pair of first swing diaphragm blades 48,and one of the pair of second swing diaphragm blades 50.

In this embodiment, the concave portion 5850 is disposed in the centerarea in the lateral direction in the lower half of the diaphragm covermember 58, as indicated by the hatched portion in FIG. 32.

The depth of the concave portion 5850 has such a size that a gap in thedirection of the optical axis can be guaranteed among the other of thepair of straight-moving diaphragm blades 46, the other of the pair offirst swing diaphragm blades 48, and the other of the pair of secondswing diaphragm blades 50.

In this embodiment, the receiving member including the diaphragm basemember 42 and the diaphragm cover member 58 has a pair of side surfacesfacing each other in the direction of the optical axis L. One of thepair of side surfaces is formed of the diaphragm cover member 58 and theother of the pair of side surfaces is formed of the diaphragm basemember 42. The concave portion 5850 is formed in the diaphragm covermember 58 which is one of the pair of side surfaces.

The assembly of the diaphragm unit 40 will be described now.

As shown in FIGS. 4 and 5, the annular plate 54 is received in theconcave portion 68 of the diaphragm base member 42 in the state wherethe straight-moving diaphragm blade driving pins 54D, the first swingdiaphragm blade driving pins 54E, and the second swing diaphragm bladedriving pins 54F of the annular plate 54 are made to face the rear side.

Subsequently, by inserting the driving pins 54D and 54E into the reliefgrooves 70B of the fixed diaphragm 70 and inserting the straight-movingdiaphragm blade driving pins 62 in the insertion holes 70C, the fixeddiaphragm 70 is attached to the diaphragm base member 42 with theannular plate 54 interposed therebetween.

Then, the partition plate 44 is attached to the diaphragm base member42.

That is, the rails 4410, 4412, 4414, 4416, and 4418 of the partitionplate 44 are made to face the rear side and the straight-movingdiaphragm blade driving pins 54D and the first swing diaphragm bladedriving pins 54E are inserted into the first insertion portions 4402. Inaddition, the second swing diaphragm blade driving pins 54F are insertedinto the second insertion portions 4404.

In addition, the first swing diaphragm blade spindles 64 and the secondswing diaphragm blade spindles 66 are inserted into the insertion holes4422 and 4424.

By allowing the engagement claws 4426 to engage with the diaphragm basemember 42, the partition plate 44 is attached to the diaphragm basemember 42 with the fixed diaphragm 70 and the annular plate 54interposed therebetween.

Then, one of the pair of straight-moving diaphragm blades 46, one of thepair of first swing diaphragm blades 48, one of the pair of second swingdiaphragm blades 50, and one of the two spacers 52 are attached to thediaphragm base member 42.

That is, as shown in FIG. 5, one second swing diaphragm blade spindle 66is inserted into the hole 5002 of the second swing diaphragm blade 50while allowing one second swing diaphragm blade 50 of the pair of secondswing diaphragm blades 50 to face the rear surface 42B of the diaphragmbase member 42. In addition, one second swing diaphragm blade drivingpin 54F is inserted into the cam groove 5004 of one second swingdiaphragm blade 50.

Subsequently, one first swing diaphragm blade spindle 64 is insertedinto the hole 4802 of one first swing diaphragm blade 48 so as tooverlap one first swing diaphragm blade 48 of the pair of first swingdiaphragm blades 48 with one second swing diaphragm blade 50. Inaddition, one first swing diaphragm blade driving pin 54E is insertedinto the cam groove 4804 of one first swing diaphragm blade 48.

Then, one straight-moving diaphragm blade guide pin is inserted into twolinear guide grooves 4602 of one straight-moving diaphragm blade 46 soas to overlap one straight-moving diaphragm blade 46 of the pair ofstraight-moving diaphragm blades 46 with the first and second swingdiaphragm blades 48 and 50 on one side. In addition, one straight-movingdiaphragm blade driving pin 54D is inserted into the cam groove 4604 ofone straight-moving diaphragm blade 46.

Subsequently, two straight-moving diaphragm blade guide pins 62 areinserted into two attachment holes 5202 of one spacer 52 so as tooverlap one spacer 52 of two spacers 52 with one straight-movingdiaphragm blade 46.

Then, the other of the pair of straight-moving diaphragm blades 46, theother of the pair of first swing diaphragm blades 48, the other of thepair of second swing diaphragm blades 50, and the other of two spacers52 are attached to the diaphragm base member 42.

That is, two straight-moving diaphragm blade guide pins 62 on the otherside are inserted into two attachment holes 5202 of the other spacer 52so as to overlap the other spacer 52 of two spacers 52 with one firstswing diaphragm blade 48.

Subsequently, the other straight-moving diaphragm blade guide pins 62are inserted into two linear guide grooves 4602 of the otherstraight-moving diaphragm blade 46 so as to overlap the otherstraight-moving diaphragm blade 46 of the pair of straight-movingdiaphragm blades 46 with two spacers 52. In addition, the otherstraight-moving diaphragm blade driving pin 54D is inserted into the camgroove 4604 of the other straight-moving diaphragm blade 46.

Subsequently, the other first swing diaphragm blade spindle 64 isinserted into the hole 4802 of the other first swing diaphragm blade 48so as to overlap the other first swing diaphragm blade 48 of the pair offirst swing diaphragm blades 48 with the other straight-moving diaphragmblade 46. In addition, the other first swing diaphragm blade driving pin54E is inserted into the cam groove 4804 of the other first swingdiaphragm blade 48.

Subsequently, the other second swing diaphragm blade spindle 66 isinserted into the hole 5002 of the other second swing diaphragm blade 50so as to overlap the other second swing diaphragm blade 50 of the pairof second swing diaphragm blades 50 with the other straight-movingdiaphragm blade 46 and the other first swing diaphragm blade 48. Inaddition, the other second swing diaphragm blade driving pin 54F isinserted into the cam groove 5004 of the other second swing diaphragmblade 50.

In this way, as shown in FIG. 31, the pair of swing diaphragm blades 46,the pair of first straight-moving diaphragm blades 48, the pair ofsecond straight-moving diaphragm blades 50, and two spacers 52 arearranged around the hole 42C. The partition plate 44, the fixeddiaphragm 70, and the annular plate 54 are interposed among the blades46, 48, and 50, the spacers 52, and the diaphragm base member 42.

Finally, as shown in FIGS. 4 and 5, the diaphragm cover member 58 isattached to the diaphragm base member 42 from the rear side of thediaphragm base member 42.

That is, the rails 5810, 5812, 5814, 5816, and 5818 of the diaphragmcover member 58 are made to face the front side and then thestraight-moving diaphragm blade driving pins 54D and the first swingdiaphragm blade driving pins 54E are inserted into the third insertionportions 5802. In addition, the second swing diaphragm blade drivingpins 54F are inserted into the fourth insertion portions 5804.

In addition, the first swing diaphragm blade spindle and the secondswing diaphragm blade spindle 66 are inserted into the insertion holes5822 and 5824.

The engagement claws 5826 are made to engage with the diaphragm basemember 42.

Accordingly, the annular plate 54, the fixed diaphragm 70, the partitionplate 44, the pair of straight-moving diaphragm blade 46, the pair offirst swing diaphragm blades 48, and the pair of second swing diaphragmblades 50, and two spacers 52, which are received in the receivingsection 60 and are attached to the diaphragm base member 42, are coveredwith the diaphragm cover member 58.

As shown in FIGS. 32 and 35, the concave portion 5850 of the diaphragmcover member 58 is disposed lower than the optical axis L.

Therefore, one second swing diaphragm blade 50, one first swingdiaphragm blade 48, one straight-moving diaphragm blade 46, the otherstraight-moving diaphragm blade 46, the other first swing diaphragmblade 48, and the other second swing diaphragm blade 50 overlap witheach other in this order on the partition plate 44.

In addition, one spacer 52 is interposed between one straight-movingdiaphragm blade 46 and the other first swing diaphragm blade 48, and theother spacer 52 is interposed between one first swing diaphragm blade 48and the other straight-moving diaphragm blade 46.

One set of swing diaphragm blades 46 and 48 out of two sets of pairs ofswing diaphragm blades 46 and 48 are disposed close to the front surfacewhich is one surface of both surfaces where the pair of straight-movingdiaphragm blades 46 faces the optical axis direction.

The other set of swing diaphragm blades 46 and 48 out of two sets ofpairs of swing diaphragm blades 46 and 48 are disposed close to the rearsurface which is the other surface of both surfaces where the pair ofstraight-moving diaphragm blades 46 faces the optical axis direction.

The pair of straight-moving diaphragm blades 46 is disposed at theopposed positions of the diaphragm opening 2 so as to linearly move inthe directions in which they get close to and apart from the opticalaxis L along the plane perpendicular to the optical axis L.

The pair of first swing diaphragm blades 48 is disposed at the opposedpositions of the diaphragm opening 2 so as to swing in the directions inwhich they get close to and apart from the optical axis L about the axisparallel to the optical axis L.

The pair of second swing diaphragm blades 50 is disposed at the opposedpositions of the diaphragm opening 2 so as to swing in the directions inwhich they get close to and apart from the optical axis L about the axisparallel to the optical axis L.

The diaphragm driving mechanism, which adjusts the size of the diaphragmopening 2 by allowing the straight-moving diaphragm blades 46 tolinearly move and allowing the first and second swing diaphragm blades48 and 50 to swing, includes the diaphragm motor 56, the driving gear56C, the gear portion 55, and the annular plate 54.

As shown in FIGS. 12 to 15, the edges of the diaphragm opening 2 in thedirection where the straight-moving diaphragm blades 46 move linearly isformed by the opening forming edge portions 44A of the straight-movingdiaphragm blades 46.

The edges of the diaphragm opening 2 in the direction perpendicular tothe direction in which the straight-moving diaphragm blades 46 linearlymove are formed by the opening forming edge portions 48A of the firstswing diaphragm blades 48 and the opening forming edge portions 50A ofthe second swing diaphragm blades 50.

As shown in FIGS. 12 to 15, the first swing diaphragm blade spindle 64(the swing point of the pair of first swing diaphragm blades 48) islocated in the extending range of the moving locus of the pair ofstraight-moving diaphragm blades 46 as viewed in the optical axisdirection.

As shown in FIGS. 12 to 15, the second swing diaphragm blade spindle 66(the swing point of the pair of second swing diaphragm blades 50) islocated in the extending range of the moving locus of the pair ofstraight-moving diaphragm blades 46 as viewed in the optical axisdirection.

As shown in FIGS. 12 to 15, the driving mechanism is located in theextending range of the moving locus of the pair of straight-movingdiaphragm blades 46 as viewed in the optical axis direction.

The operation of the diaphragm unit 40 will be described now.

As shown in FIG. 12, the case where the diaphragm opening 2 is open willbe first described.

The straight-moving diaphragm blade guide pin 62 is located at one endin the longitudinal direction of the linear guide groove 4602 of thestraight-moving diaphragm blade 46.

The first swing diaphragm blade driving pin 54E is located at one end inthe longitudinal direction of the cam groove 4804 of the first swingdiaphragm blade 48 and the second swing diaphragm blade driving pin 54Fis located at one end in the longitudinal direction of the cam groove5004 of the second swing diaphragm blade 50.

In this state, the diaphragm opening 2 is formed in a substantiallycircular shape by the opening forming edge portions 46A of the pair ofstraight-moving diaphragm blades 46, the opening forming edge portions48A of the pair of first swing diaphragm blades 48, and the openingforming edge portions 50A of the pair of second swing diaphragm blades50.

In this embodiment, the diameter of the diaphragm opening 2 and thediameter of the hole 70A of the fixed diaphragm 70 are equal to eachother in the open state.

Here, when the annular plate 54 rotates by a predetermined amount byforwardly rotationally driving the diaphragm motor 56, thestraight-moving diaphragm blade driving pins 54D engaging with the camgrooves 4404 of the pair of straight-moving diaphragm blades 46 swing.

Accordingly, the straight-moving diaphragm blades 46 linearly move by apredetermined amount via the guide grooves 4402 and the straight-movingdiaphragm blade guide pins 62 engaging with the guide grooves 4402.

As a result, as shown in FIG. 13, the gap between the facing openingforming edge portions 46A of the pair of straight-moving diaphragmblades 46, that is, the diameter of the diaphragm opening 2, is reduced.

When the annular plate 54 rotates by a predetermined amount, the pair offirst swing diaphragm blades 48 swings about the first swing diaphragmblade spindle 64 by a predetermined amount via the cam grooves 4604 bythe swing of the first swing diaphragm blade driving pins 54E.

Accordingly, as shown in FIG. 13, the gap between the facing openingforming edge portions 48A of the pair of first swing diaphragm blades48, that is, the diameter of the diaphragm opening 2, is reduced.

When the annular plate 54 rotates by a predetermined amount, the pair ofsecond swing diaphragm blades 50 swings about the second swing diaphragmblade spindle 66 by a predetermined amount via the cam grooves 4804 bythe swing of the second swing diaphragm blade driving pins 54F.

Accordingly, as shown in FIG. 13, the gap between the facing openingforming edge portions 50A of the pair of second swing diaphragm blades50, that is, the diameter of the diaphragm opening 2, is reduced.

At this time, three gaps of the gap between the opening forming edgeportions 46A of the pair of straight-moving diaphragm blades 46, the gapbetween the opening forming edge portions 48A of the pair of first swingdiaphragm blades 48, and the gap between the opening forming edgeportions 50A of the pair of second swing diaphragm blades 50 havesubstantially the same size.

In other words, the diameter of diaphragm opening 2 formed by the pairof straight-moving diaphragm blades 46, the diameter of diaphragmopening 2 formed by the pair of first swing diaphragm blades 48, and thediameter of diaphragm opening 2 formed by the pair of second swingdiaphragm blades 50 are equal to each other.

As a result, the diaphragm opening 2 formed by the opening forming edgeportions 46A of the pair of straight-moving diaphragm blades 46, theopening forming edge portions 48A of the pair of first swing diaphragmblades 48, and the opening forming edge portions 50A of the pair ofsecond swing diaphragm blades 50 is reduced in size.

In FIG. 13, the diaphragm opening 2 is narrowed by one step and theshape of the diaphragm opening 2 becomes a substantially regularhexagonal shape by the opening forming edge portions 46A, 48A, and 50A.

In the course where the diaphragm opening 2 is changed from the openstate shown in FIG. 12 to the state narrowed by one step in FIG. 13, theshape of the diaphragm opening 2 is continuously changed from thesubstantially circular shape to the substantially regular hexagonalshape.

When the diaphragm motor 56 is additionally rotationally driven forwardfrom the state shown in FIG. 13 and the annular plate 54 furtherrotates, the pair of straight-moving diaphragm blades 46 linearly movesin the above-mentioned operating way. In addition, the pair of firstswing diaphragm blades 48 and the pair of second swing diaphragm blades50 swing.

Accordingly, as shown in FIG. 14, the diaphragm opening 2 formed by theopening forming edge portions 46A of the pair of straight-movingdiaphragm blades 46, the opening forming edge portions 48A of the pairof first swing diaphragm blades 48, and the opening forming edgeportions 50A of the pair of second swing diaphragm blades 50 is furtherreduced in size.

In FIG. 14, the diaphragm opening 2 is narrowed by six steps and theshape of the diaphragm opening 2 is changed to a substantially regularhexagonal shape by the opening forming edge portions 46A, 48A, and 50A.

When the diaphragm motor 56 is additionally rotationally driven forwardfrom the state shown in FIG. 14 and the annular plate 54 furtherrotates, the pair of straight-moving diaphragm blades 46 linearly movesin the above-mentioned operating way. In addition, the first swingdiaphragm blades 48 and the second swing diaphragm blades 50 swing.

Accordingly, the diaphragm opening 2 formed by the opening forming edgeportions 46A of the pair of straight-moving diaphragm blades 46, theopening forming edge portions 48A of the pair of first swing diaphragmblades 48, and the opening forming edge portions 50A of the pair ofsecond swing diaphragm blades 50 is further reduced in size. Finally, asshown in FIG. 15, the diaphragm opening 2 is completely closed.

In the closed state, the straight-moving diaphragm blade guide pins 62are located at the outer ends in the longitudinal direction of the guidegrooves 4402 of the pair of straight-moving diaphragm blades 46.

The first swing diaphragm blade driving pins 54E are located at theouter ends in the longitudinal direction of the cam grooves 4604 of thepair of first swing diaphragm blades 48, and the second swing diaphragmblade driving pins 54F are located at the outer ends in the longitudinaldirection of the cam grooves 4804 of the pair of second swing diaphragmblades 50.

When the diaphragm motor 56 is rotationally driven backward from theclosed state shown in FIG. 15 and the annular plate 54 rotates in thereverse direction of the above-mentioned direction, the pair ofstraight-moving diaphragm blades 46 linearly moves in the reversedirection to the above-mentioned direction and the pair of first swingdiaphragm blades 48 and the pair of second swing diaphragm blades 50swing in the reverse direction of the above-mentioned direction.

Accordingly, the diaphragm opening 2 is formed by the opening formingedge portions 46A of the pair of straight-moving diaphragm blades 46,the opening forming edge portions 48A of the pair of first swingdiaphragm blades 48, and the opening forming edge portions 50A of thepair of second swing diaphragm blades 50.

Then, as shown in FIGS. 14 and 13, the diaphragm opening 2 is formed andthe diaphragm opening 2 is gradually enlarged by the rotational drivingof the diaphragm motor 56 in the reverse direction, and the diaphragmopening 2 is finally completely opened as shown in FIG. 12.

In the course where the diaphragm opening 2 is changed from the statewhere it is narrowed by one step in FIG. 13 to the state where it iscompletely opened in FIG. 12, the shape of the diaphragm opening 2 iscontinuously changed from the substantially regular hexagonal shape tothe substantially circular shape.

Therefore, by controlling the rotation direction and the rotation amountof the diaphragm motor 56, the diaphragm opening 2 of the diaphragm unit40 is adjusted between the open state and the closed state.

The function of the spacers 52 will be described now.

FIG. 25 is an enlarged view illustrating the vicinity of the spacer 52.FIG. 26 is an enlarged view where the spacer 52 is removed from FIG. 25.

The spacers 52 serve to smooth the swing of a pair of first swingdiaphragm blades 48.

That is, as shown in FIG. 26, the edge 4810 of the other first swingdiaphragm blade 48 out of two first swing diaphragm blades 48 is locatedin the linear guide groove 4602 of one straight-moving diaphragm blade46 out of two straight-moving diaphragm blades 46.

Accordingly, when the edge 4810 swings in the direction getting close tothe linear guide groove 4602, the edge 4810 may interfere with the edgeof the linear guide groove 4602, thereby hindering the smooth swing ofthe first swing diaphragm blade 48.

Therefore, in this embodiment, as shown in FIG. 25, the spacer 52 isinterposed between the linear guide groove 4602 of one straight-movingdiaphragm blade 46 and the edge 4810 of the other first swing diaphragmblade 48. In other words, the straight-moving diaphragm blade 46 and thefirst swing diaphragm blade 48 are separated in the thickness directionthereof by the spacer 52.

Accordingly, the interference of the edge 4810 with the edge of thelinear guide groove 4602 is prevented, thereby smoothing the swing ofthe other first swing diaphragm blade 48 out of two first swingdiaphragm blades 48.

The other spacer 52 out of two spacers 52 is interposed between thelinear guide groove 4602 of the other straight-moving diaphragm blade 46out of two straight-moving diaphragm blades 46 and the edge 4810 of onefirst swing diaphragm blade 48 out of two first swing diaphragm blades48.

Accordingly, as described above, the swing of one first swing diaphragmblade 48 out of two first swing diaphragm blades 48 is smoothed.

FIG. 16 is a plan view illustrating the position of one second swingdiaphragm blade 50 when the diaphragm opening 2 is open.

FIG. 17 is a plan view illustrating the position of one second swingdiaphragm blade 50 when the diaphragm opening 2 is completely closed.

FIG. 18 is a plan view illustrating the positions of one straight-movingdiaphragm blade 46, one first swing diaphragm blade 48, and one secondswing diaphragm blade 50 when the diaphragm opening 2 is open.

FIG. 19 is a plan view illustrating the positions of one straight-movingdiaphragm blade 46, one first swing diaphragm blade 48, and one secondswing diaphragm blade 50 when the diaphragm opening 2 is completelyclosed.

FIG. 20 is a sectional view illustrating the partition plate 44, onestraight-moving diaphragm blade 46, one first swing diaphragm blade 48,and one second swing diaphragm blade 50.

The functions of the rails formed in the partition plate 44 will bedescribed in detail now.

As shown in FIG. 20, one second swing diaphragm blade 50 of the pair ofsecond swing diaphragm blades 50, one first swing diaphragm blade 48 ofthe pair of first swing diaphragm blades 48, and one straight-movingdiaphragm blade 46 of the pair of straight-moving diaphragm blades 46overlap with each other on the partition plate 44 in that order.

As shown in FIGS. 18 and 19, the first rail 4410 guiding onestraight-moving diaphragm blade 46 is disposed in the moving locus ofone straight-moving diaphragm blade 46 and has a height sufficient toguide one straight-moving diaphragm blade 46.

As shown in FIGS. 16 and 17, the second rail 4412 guiding one secondswing diaphragm blade 50 is disposed in the moving locus of one secondswing diaphragm blade 50 and has a height sufficient to guide one secondswing diaphragm blade 50. The height of the second rail 4412 isdifferent from the height of the first rail 4410.

As shown in FIGS. 16 and 17, the first and second rails 4410 and 4412are disposed outside the moving locus of the first swing diaphragmblades 48.

As a result, one straight-moving diaphragm blade 46 is smoothly guidedby the first rail 4410 without coming in contact with the second rail4412.

One second swing diaphragm blade 50 is smoothly guided by the secondrail 4412 without coming in contact with the first rail 4410.

As shown in FIG. 20, the first swing diaphragm blade swings withoutcoming in contact with the plural rails formed in the partition plate 44in the state where it is interposed between the straight-movingdiaphragm blade 46 and the second swing diaphragm blade 50.

In this embodiment, since one straight-moving diaphragm blade 46 is alsoguided by the eighth rail 5814 formed in the diaphragm cover member 58shown in FIG. 11, one straight-moving diaphragm blade 46 can move moresmoothly.

As shown in FIG. 11, the functions of the rails formed in the diaphragmcover member 58 are the same as the functions of the rails formed in thepartition plate 44.

As shown in FIG. 5, the other straight-moving diaphragm blade 46 of thepair of straight-moving diaphragm blades 46, the other first swingdiaphragm blade 48 of the pair of first swing diaphragm blades 48, andthe other second swing diaphragm blade 50 of the pair of second swingdiaphragm blades 50 overlap with each other on the pair of spacers 52 inthat order.

The sixth rail 5810 guiding the other straight-moving diaphragm blade 46is disposed in the moving locus of the other straight-moving diaphragmblade 46 and has a height sufficient to guide the other straight-movingdiaphragm blade 46.

The seventh rail 5812 guiding the other second swing diaphragm blade 50is disposed in the moving locus of the other second swing diaphragmblade 50 and has a height sufficient to guide the other second swingdiaphragm blade 50. The height of the seventh rail 5812 is differentfrom the height of the sixth rail 5810.

The sixth and seventh rails 5810 and 5812 are disposed outside themoving locus of the first swing diaphragm blades 48.

As a result, the other straight-moving diaphragm blade 46 is smoothlyguided by the sixth rail 5810 without coming in contact with the seventhrail 5812.

The other second swing diaphragm blade 50 is smoothly guided by theseventh rail 5812 without coming in contact with the sixth rail 5810.

The first swing diaphragm blade 48 swings without coming in contact withthe plural rails formed in the partition plate 44 in the state where itis interposed between the straight-moving diaphragm blade 46 and thesecond swing diaphragm blade 50.

Accordingly, since the other straight-moving diaphragm blade 46 and theother second swing diaphragm blade 50 are smoothly guided by the sixthand seventh rails 5810 and 5812, the movement is stabilized.

Since the other straight-moving diaphragm blade 46, the other firstswing diaphragm blade 48, and the other second swing diaphragm blade 50are separated from the annular plate by the partition plate 44 and donot contact with the annular plate 54, the frictional load is reduced.

In this embodiment, since the other straight-moving diaphragm blade 46is also guided by the third rail 4414 formed in the partition plate 44shown in FIG. 10, the other straight-moving diaphragm blade 46 can movemore smoothly.

According to this diaphragm unit 40, as shown in FIGS. 32 and 35, sincethe concave portion 5850 is disposed in the diaphragm cover member 58,it is possible to reduce the size of the lens barrel in the direction ofthe optical axis L by receiving and arranging another optical device ora part thereof, or an optical member or a part thereof in the concaveportion 5850. Therefore, it is advantageous for the decrease in size ofthe imaging apparatus.

Alternatively, by receiving another optical device or a part thereof inthe concave portion 5850, it is possible to reduce the sizes of thedevices. Accordingly, it is possible to guarantee the great strokes ofthe movable lenses such as a zoom lens and a focus lens without anincrease in length of the lens barrel.

Accordingly, since it is possible to guarantee the zoom ratio or toguarantee a great focus adjusting range, thereby improving the opticalperformance of the lens barrel.

Since it is possible to guarantee the great strokes of the movablelenses such as a zoom lens and a focus lens without an increase inlength of the lens barrel, an inexpensive lens with a relatively smallrefractive index and a large thickness can be used as the movable lens,thereby decreasing the cost of the imaging apparatus.

A specific example where a part of the ND filter unit 41 is received inthe concave portion 5850 of the diaphragm cover member 58 to reduce thesize of the diaphragm unit 40 and the ND filter unit 41 in the directionof the optical axis L will be described now.

FIG. 27 is an exploded perspective view of the light intensity adjustingdevice 39. FIG. 28 is a perspective view of the light intensityadjusting device 39 as viewed from the front side.

FIG. 29 is an exploded perspective view of the ND filter unit 41. FIG.30 is a perspective view of the filter support member 74 to which the NDfilter 72 is attached.

FIG. 31 is a perspective view of the diaphragm unit from which thediaphragm cover member 58 is detached as viewed from the rear side. FIG.32 is a perspective view of the diaphragm unit 40 to which the diaphragmcover member 58 is attached as viewed from the rear side.

FIG. 33 is a perspective view illustrating a state where the filtercover member 82 is attached to the diaphragm unit 40. FIG. 34 is aperspective view illustrating a state where the filter cover member 82is attached to the filter support member 74 in FIG. 33.

FIG. 35 is a sectional view taken along line AA of FIG. 34 where the NDfilter 72 is located at the retreating position. FIG. 36 is a sectionalview taken along line AA of FIG. 34 where the ND filter 72 is located atthe in-use position.

FIG. 37 is a sectional view of the light intensity adjusting device 39where the ND filter 72 is located at the retreating position.

As shown in FIGS. 27 and 29, the ND filter unit 41 includes an ND filter72, a filter support member 74, a filter driving mechanism 76, and acase 78.

The case 78 includes a filter base member 80 and a filter cover member82.

As shown in FIGS. 35, 36, and 37, the ND filter unit 41 is disposed tooverlap with the diaphragm cover member 58.

The ND filter 72 is a filter for reducing the transmitted lightintensity without changing the waveform components of the incident lightand as shown in FIGS. 35 and 36, moves between an in-use position insidethe diaphragm opening 2 and a retreating position outside the diaphragmopening 2 as viewed in the direction of the optical axis L.

As shown in FIGS. 30 and 34, the filter support member 74 serves tosupport the ND filter 72.

The filter support member 74 is formed of a flat thin plate of asynthetic resin not transmitting light.

Both sides of the filter support member 74 are provided with a guideportion 7402 formed of a longitudinal groove and guided to be movable inthe up-down directions by the filter base member 80 (FIG. 29).

The filter support member 74 includes an optical path forming cutout7404. The edges of the ND filter 72 are attached to overlap with theedges of the cutout 7404 with an adhesive. Accordingly, the ND filter 72is disposed in the filter support member 74 to cover the cutout 7404.

A cam groove 7406 for allowing the filter support member 74 to linearlymove in the up-down directions is formed in the lower part of the filtersupport member 74.

Therefore, as shown in FIG. 29, the ND filter 72 protrudes from thefilter support member 74 to the filter cover member 82 as viewed in thethickness direction of the filter support member 74.

The filter base member 80 is formed in a plate shape out of a syntheticresin as shown in FIG. 29.

An optical path opening 8002 is formed in the filter base member 80.

A filter motor 84 is attached to a position of the filter base member 80opposed to the diaphragm unit 40 below the optical path opening 8002.

The filter motor 84 serves to rotationally drive the driving gear 56Cforward and backward on the basis of the driving current supplied fromthe motor driver 43 (see FIG. 3).

The filter motor 84 includes an arm 8402 connected to the output shaftof the filter motor 84 and a pin 8404 at the end of the arm 8402 engageswith the cam groove 7406 of the filter support member 74.

With the forward and backward rotation of the filter motor 84, thefilter support member 74 is made to move up and down by the arm 8402,thereby allowing the ND filter 72 to protrude into the diaphragm opening2.

Guide pins 8004, which engage with the longitudinal grooves of the guideportions 7402 of the filter support member 74 and guide the filtersupport member 74 to linearly move in the up-down directions, protrudefrom the positions of the filter base member 80 facing the filtersupport member 74 on both lateral sides of the optical path opening8002.

In this embodiment, the filter driving mechanism 76 includes the filtermotor 84, the arm 8402, the pins 8404, the cam groove 7406, the guidepins 8004, and the guide portions 7402.

The filter cover member 82 is attached to the filter base member 80 tocover the filter support member 74, as shown in FIGS. 29 and 37.

The filter cover member 82 is formed of a synthetic-resin thin plate.

The optical path opening 8202 is formed in the filter cover member 82.Locking holes 8204 locked to the guide pins 8004 are formed on bothlateral sides of the optical path opening 8202.

A longitudinal groove 8206 for guaranteeing the swing of the pin 8404 isformed in the filter cover member 82.

The filter cover member 82 is disposed to overlap with the diaphragmcover member 58.

A protruding portion 8210 which protrudes to the diaphragm cover member58 and receives the ND filter 72 at the retreating position is formed inthe filter cover member 82.

As indicated by the hatched part in FIG. 33, the protruding portion 8210includes an end portion 8202A of the optical path opening 8202 in adirection getting apart from the optical axis L.

The ND filter unit 41 is attached to the diaphragm base member 42 of thediaphragm unit 40 by receiving the protruding portion 8210 in theconcave portion 5850, as shown in FIG. 37.

The operation of the light intensity adjusting device 39 including theND filter unit 41 will be described now.

As shown in FIGS. 35 and 37, the case where the ND filter 72 is locatedat the retreating position will be first described.

That is, the ND filter 72 is located outside the diaphragm opening 2 asviewed in the direction of the optical axis L.

Here, by controlling the rotation direction and the rotation amount ofthe diaphragm motor 56 as described above, the diaphragm opening 2 ofthe diaphragm device 40 is adjusted between the open state and theclosed state, and the beam of light narrowed by the diaphragm opening 2formed by the diaphragm unit 40 reaches the imaging device 18.

As the diaphragm opening 2 of the diaphragm unit 40 decreases in size,the light intensity of the beam of light forming a subject image passingthrough the diaphragm unit 40 can be reduced. However, when thediaphragm opening 2 becomes too small, the diffraction occurs in thediaphragm opening 2, thereby badly influencing the image quality imagedby the imaging device 18.

Accordingly, the lower limit (minimum diaphragm) in size of thediaphragm opening 2 of the diaphragm unit 40 should be set not to causethe diffraction, and the ND filter 72 is used to further reduce thelight intensity.

When the ND filter 72 is used and the arm 8402 swings by a predeterminedamount by rotationally driving the filter motor 84 forward by apredetermined amount, the filter support member 74 is made to linearlymove by a predetermined amount by the pin 8404 of the arm 8402.

As a result, as shown in FIG. 36, the ND filter 72 is located inside thediaphragm opening 2 as viewed in the direction of the optical axis L.That is, the ND filter 72 is located at the in-use position.

The ND filter 72 is located in the inside in the radial direction of theoptical path opening 8202 at the in-use position as viewed in thedirection of the optical axis L, and is located at the positionoverlapping with the thickness range of the filter cover member 82 asviewed in the direction perpendicular to the optical axis L.

By positioning the ND filter 72 at the in-use position, the beam oflight narrowed by the diaphragm opening 2 of the diaphragm unit 40decreases in light intensity while passing through the ND filter 72 andthen reaches the imaging device 18. Accordingly, the imaging device 18can perform an imaging operation without any influence of thediffraction.

By rotationally driving the filter motor 84 backward by a predeterminedamount, as shown in FIGS. 35 and 37, the ND filter 72 is returned to theretreating position.

As described above, according to this embodiment, since the protrudingportion 8210 of the filter cover member is received in the concaveportion 5850 disposed in the diaphragm cover member 58 and the ND filter72 located at the retreating position is received in the protrudingportion 8210, it is possible to reduce the size of the light intensityadjusting device 39 in the direction of the optical axis L. Therefore,it is possible to reduce the size of the lens barrel, thereby reducingthe size of the imaging apparatus.

Alternatively, by reducing the size of the light intensity adjustingdevice 39 in the direction of the optical axis L, it is possible toguarantee the strokes of the movable lenses as described above, therebyimproving the optical performance of the lens barrel. Since aninexpensive lens with a relatively small refractive index and a greatthickness can be used as the movable lens, it is possible to reduce thecost of the imaging apparatus.

The embodiment of the invention will be now compared with comparativeexamples with reference to FIGS. 39 to 41.

FIG. 39 is a sectional view of a diaphragm unit 40A according toComparative Example 1.

FIG. 40 is a sectional view of a diaphragm unit 40B according toComparative Example 2. FIG. 41 is a plan view of diaphragm bladesaccording to Comparative Example 2.

The same elements and members of Comparative Examples 1 and 2 as theembodiment of the invention are referenced and described by the samereference numerals and signs.

Comparative Example 1 relates to a diaphragm unit 40A in which theconcave portion 5850 is not formed in the diaphragm cover member 58 andthe configurations of the diaphragm blades are the same as theabove-mentioned embodiment.

The diaphragm unit 40A is formed in a flat plate shape in which thediaphragm cover member 58 does not include the concave portion 5850.

To correspond to this configuration, the filter cover member 82 of theND filter unit 41 is formed in a flat plate shape.

In this embodiment, as shown in FIG. 37, a space S is secured betweenthe ND filter 72 and the filter cover member 82 at the retreatingposition of the ND filter 72. The space S serves to prevent the contactof the ND filter 72 with the filter cover member 82.

On the other hand, in the diaphragm unit 40A, as shown in FIG. 39, aspace S is secured between the ND filter 72 and the entire region of thefilter cover member 82.

Therefore, in the upper half of FIG. 37 and the upper half of FIG. 39,the distance D1 from the front surface 42A of the diaphragm base member42 to the front surface 82A of the filter cover member 82 is constant.

However, in this embodiment, the distance D2 from the front surface 42Ato the front surface of the ND filter 72 is smaller than that ofComparative example 1 by the depth of the concave portion 5850.

In this embodiment, the distance D3 from the front surface 42A to therear surface of the filter base member 80 is smaller than that ofComparative Example 1 by the depth of the concave portion 5850.

Therefore, according to this embodiment, it is possible to reduce thesize of the light intensity adjusting device 39 in the optical axisdirection in comparison with Comparative Example 1.

This embodiment will be compared with Comparative Example 2.

The diaphragm unit 40B according to Comparative Example 2 employs theiris diaphragm shown in FIG. 41.

The iris diaphragm serves to expand or contract the diaphragm opening 2by allowing the plural diaphragm blades 90 overlapping with each otheron the circumference centered on the optical axis to swing around theshaft 92 parallel to the optical axis.

As shown in FIG. 40, the diaphragm unit 40B should guarantee a space forallowing the plural diaphragm blades 92 to swing in the overlappingstate along the circumference centered on the optical axis L.

In consideration of this structure, it is not possible to form theconcave portion 5850 in the diaphragm cover member 58.

Therefore, in Comparative Example 2, similarly to Comparative Example 1,it is difficult to reduce the size of the light intensity adjustingdevice 39 in the direction of the optical axis L, compared with thisembodiment.

Second Embodiment

A second embodiment of the invention will be described now.

FIG. 38 is a sectional view of a light intensity adjusting device 39according to the second embodiment of the invention.

The second embodiment is different from the first embodiment, in thatthe filter cover member 82 and the diaphragm cover member 58 are formedof a single member, as shown in FIG. 38.

When it is considered that the filter cover member serves as thediaphragm cover member 58 of the diaphragm unit 40, the concave portion5850 is formed in the filter cover member 82.

When it is considered that the filter cover member 82 serves as thefilter cover member 82 of the ND filter unit 41, the convex portion 8210is formed in the filter cover member 82.

According to the second embodiment, since the filter cover member 82 andthe diaphragm cover member 58 are formed of a single member, it ispossible to reduce the size of the light intensity adjusting device 39in the direction of the optical axis by the thickness of one covermember.

Although it has been described in this embodiment that the diaphragmunit 40 has six diaphragm blades of a pair of straight-moving diaphragmblades 46, a pair of first swing diaphragm blades 48, and a pair ofsecond swing diaphragm blades 50, the diaphragm unit 40 may have a pairof straight-moving diaphragm blades and a pair of swing diaphragmblades. In this case, plural sets of swing diaphragm blades may beprovided as the pair of swing diaphragm blades, the number of diaphragmblades may be four or eight or more.

Although it has been described in this embodiment that the imagingapparatus is a video camera, the invention can be widely applied toimage apparatuses such as a digital still camera, a camera-mountedmobile phone, and a monitoring camera.

Although it has been described in this embodiment that the diaphragmunit is applied to the imaging apparatus, the invention is not limitedto this configuration, but the diaphragm unit according to theembodiment of the invention may be used, for example, as a diaphragmunit of a light source in a projector.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A diaphragm unit comprising: a pair of straight-moving diaphragmblades and a pair of swing diaphragm blades overlapping with each otherin an optical axis direction of an optical system and forming adiaphragm opening centered on the optical axis by moving in directionsin which the diaphragm blades get close to and apart from the opticalaxis along a plane perpendicular to the optical axis; a receiving memberreceiving the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades; and a diaphragm driving mechanism adjusting thesize of the diaphragm opening by moving the diaphragm blades, whereinthe receiving member has a pair of side surfaces facing each other inthe optical axis direction, wherein one of the pair of straight-movingdiaphragm blades and one of the pair of swing diaphragm blades aredisposed on one of the pair of side surfaces, wherein the other of thepair of straight-moving diaphragm blades and the other of the pair ofswing diaphragm blades are disposed on the other of the pair of sidesurfaces, and wherein a concave portion which is concave toward theother of the pair of side surfaces is disposed on one of the pair ofside surfaces outside the moving locus of one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades in a state where a space is secured in the optical axis directionbetween the other of the pair of straight-moving diaphragm blades andthe other of the pair of swing diaphragm blades.
 2. The diaphragm unitaccording to claim 1, wherein the receiving member includes a diaphragmbase member and a diaphragm cover member, wherein the diaphragm basemember is formed of a synthetic resin plate and has a receiving sectionreceiving the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades, wherein the diaphragm cover member is formed ofa steel plate and is attached to the diaphragm base member to cover thepair of straight-moving diaphragm blades and the pair of swing diaphragmblades received in the receiving section, wherein one of the pair ofside surfaces is formed of the diaphragm cover member, and wherein theother of the pair of side surfaces is formed of the diaphragm basemember.
 3. A light intensity adjusting device comprising: a diaphragmunit adjusting the size of a diaphragm opening centered on an opticalaxis of an optical system; and an ND filter unit reducing the lightintensity passing through the diaphragm opening, wherein the diaphragmunit includes a pair of straight-moving diaphragm blades and a pair ofswing diaphragm blades overlapping with each other in the optical axisdirection of the optical system and forming the diaphragm openingcentered on the optical axis by moving in directions in which thediaphragm blades get close to and apart from the optical axis along aplane perpendicular to the optical axis, a diaphragm base member havinga receiving section receiving the pair of straight-moving diaphragmblades and the pair of swing diaphragm blades, a diaphragm cover membercovering the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades received in the receiving section, and adiaphragm driving mechanism adjusting the size of the diaphragm openingby moving the diaphragm blades, wherein one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades are disposed close to the diaphragm cover member, wherein theother of the pair of straight-moving diaphragm blades and the other ofthe pair of swing diaphragm blades are disposed close to the diaphragmbase member, wherein a concave portion which is concave toward the otherof the pair of side surfaces is disposed close to the diaphragm basemember outside the moving locus of one of the pair of straight-movingdiaphragm blades and one of the pair of swing diaphragm blades in astate where a space is secured in the optical axis direction between theother of the pair of straight-moving diaphragm blades and the other ofthe pair of swing diaphragm blades, wherein the ND filter unit includesan ND filter moving between an in-use position located inside thediaphragm opening and a retreating position located outside thediaphragm opening as viewed in the optical axis direction, and a casereceiving the ND filter, wherein the case has a side surface overlappingwith the diaphragm cover member, wherein a convex portion protruding tothe side surface of the diaphragm cover member and receiving the NDfilter at the retreating position is formed on the side surface, andwherein the convex portion is received in the concave portion.
 4. A lensbarrel comprising a diaphragm unit, wherein the diaphragm unit includes:a pair of straight-moving diaphragm blades and a pair of swing diaphragmblades overlapping with each other in an optical axis direction of anoptical system and forming a diaphragm opening centered on the opticalaxis by moving in directions in which the diaphragm blades get close toand apart from the optical axis along a plane perpendicular to theoptical axis; a receiving member receiving the pair of straight-movingdiaphragm blades and the pair of swing diaphragm blades; and a diaphragmdriving mechanism adjusting the size of the diaphragm opening by movingthe diaphragm blades, wherein the receiving member has a pair of sidesurfaces facing each other in the optical axis direction, wherein one ofthe pair of straight-moving diaphragm blades and one of the pair ofswing diaphragm blades are disposed on one of the pair of side surfaces,wherein the other of the pair of straight-moving diaphragm blades andthe other of the pair of swing diaphragm blades are disposed on theother of the pair of side surfaces, and wherein a concave portion whichis concave toward the other of the pair of side surfaces is disposed onone of the pair of side surfaces outside the moving locus of one of thepair of straight-moving diaphragm blades and one of the pair of swingdiaphragm blades in a state where a space is secured in the optical axisdirection between the other of the pair of straight-moving diaphragmblades and the other of the pair of swing diaphragm blades.
 5. A lensbarrel comprising a light intensity adjusting device adjusting the lightintensity passing through an optical system, wherein the light intensityadjusting device includes: a diaphragm unit adjusting the size of adiaphragm opening centered on an optical axis of the optical system; andan ND filter unit reducing the light intensity passing through thediaphragm opening, wherein the diaphragm unit includes a pair ofstraight-moving diaphragm blades and a pair of swing diaphragm bladesoverlapping with each other in the optical axis direction of the opticalsystem and forming the diaphragm opening centered on the optical axis bymoving in directions in which the diaphragm blades get close to andapart from the optical axis along a plane perpendicular to the opticalaxis, a diaphragm base member having a receiving section receiving thepair of straight-moving diaphragm blades and the pair of swing diaphragmblades, a diaphragm cover member covering the pair of straight-movingdiaphragm blades and the pair of swing diaphragm blades received in thereceiving section, and a diaphragm driving mechanism adjusting the sizeof the diaphragm opening by moving the diaphragm blades, wherein one ofthe pair of straight-moving diaphragm blades and one of the pair ofswing diaphragm blades are disposed close to the diaphragm cover member,wherein the other of the pair of straight-moving diaphragm blades andthe other of the pair of swing diaphragm blades are disposed close tothe diaphragm base member, wherein a concave portion which is concavetoward the other of the pair of side surfaces is disposed close to thediaphragm base member outside the moving locus of one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades in a state where a space is secured in the optical axis directionbetween the other of the pair of straight-moving diaphragm blades andthe other of the pair of swing diaphragm blades, wherein the ND filterunit includes an ND filter moving between an in-use position locatedinside the diaphragm opening and a retreating position located outsidethe diaphragm opening as viewed in the optical axis direction, and acase receiving the ND filter, wherein the case has a side surfaceoverlapping with the diaphragm cover member, wherein a convex portionprotruding to the side surface of the diaphragm cover member andreceiving the ND filter at the retreating position is formed on the sidesurface, and wherein the convex portion is received in the concaveportion.
 6. The lens barrel according to claim 5, wherein the ND filterunit includes: a filter support member to which the ND filter isattached; a filter base member supporting the filter support member tobe movable in directions getting close to and apart from the opticalaxis along the plane perpendicular to the optical axis; a filter covermember attached to the filter base member to cover the filter supportmember attached to the filter base member; and a filter drivingmechanism moving the filter support member so that the ND filter islocated at the in-use position or at the retreating position, whereinthe case includes the filter base member and the filter cover member,wherein the filter base member is located at a position apart from thediaphragm cover member in the optical axis direction, wherein the filtercover member is disposed to overlap with the diaphragm cover member, andwherein the convex portion is formed in the filter cover member.
 7. Thelens barrel according to claim 6, wherein the filter cover member andthe diaphragm cover member are formed of a single member.
 8. The lensbarrel according to claim 6, wherein the filter cover member has anopening with an outline larger than the ND filter at a positionincluding the optical axis, wherein the convex portion includes an endof the opening in the direction apart from the optical axis direction,and wherein the ND filter at the in-use position is located in theinside in the radial direction of the opening as viewed in the opticalaxis direction and at a position overlapping with the thickness range ofthe filter cover member as viewed in the direction perpendicular to theoptical axis.
 9. The lens barrel according to claim 8, wherein anoptical path forming cutout is formed in the filter support member,wherein the ND filter is attached to the filter support member in anoverlapping manner to cover the cutout, and wherein the ND filter islocated closer to the side surface of the filter cover member than thefilter support member in the optical axis direction.
 10. An imagingapparatus comprising a lens barrel mounted with a diaphragm unit,wherein the diaphragm unit includes: a pair of straight-moving diaphragmblades and a pair of swing diaphragm blades overlapping with each otherin an optical axis direction of an optical system and forming adiaphragm opening centered on the optical axis by moving in directionsin which the diaphragm blades get close to and apart from the opticalaxis along a plane perpendicular to the optical axis; a receiving memberreceiving the pair of straight-moving diaphragm blades and the pair ofswing diaphragm blades; and a diaphragm driving mechanism adjusting thesize of the diaphragm opening by moving the diaphragm blades, whereinthe receiving member has a pair of side surfaces facing each other inthe optical axis direction, wherein one of the pair of straight-movingdiaphragm blades and one of the pair of swing diaphragm blades aredisposed on one of the pair of side surfaces, wherein the other of thepair of straight-moving diaphragm blades and the other of the pair ofswing diaphragm blades are disposed on the other of the pair of sidesurfaces, and wherein a concave portion which is concave toward theother of the pair of side surfaces is disposed on one of the pair ofside surfaces outside the moving locus of one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades in a state where a space is secured in the optical axis directionbetween the other of the pair of straight-moving diaphragm blades andthe other of the pair of swing diaphragm blades.
 11. An imagingapparatus comprising a lens barrel mounted with a light intensityadjusting device, wherein the light intensity adjusting device includes:a diaphragm unit adjusting the size of a diaphragm opening centered onan optical axis of the optical system; and an ND filter unit reducingthe light intensity passing through the diaphragm opening, wherein thediaphragm unit includes a pair of straight-moving diaphragm blades and apair of swing diaphragm blades overlapping with each other in theoptical axis direction of the optical system and forming the diaphragmopening centered on the optical axis by moving in directions in whichthe diaphragm blades get close to and apart from the optical axis alonga plane perpendicular to the optical axis, a diaphragm base memberhaving a receiving section receiving the pair of straight-movingdiaphragm blades and the pair of swing diaphragm blades, a diaphragmcover member covering the pair of straight-moving diaphragm blades andthe pair of swing diaphragm blades received in the receiving section,and a diaphragm driving mechanism adjusting the size of the diaphragmopening by moving the diaphragm blades, wherein one of the pair ofstraight-moving diaphragm blades and one of the pair of swing diaphragmblades are disposed close to the diaphragm cover member, wherein theother of the pair of straight-moving diaphragm blades and the other ofthe pair of swing diaphragm blades are disposed close to the diaphragmbase member, wherein a concave portion which is concave toward the otherof the pair of side surfaces is disposed close to the diaphragm basemember outside the moving locus of one of the pair of straight-movingdiaphragm blades and one of the pair of swing diaphragm blades in astate where a space is secured in the optical axis direction between theother of the pair of straight-moving diaphragm blades and the other ofthe pair of swing diaphragm blades, wherein the ND filter unit includesan ND filter moving between an in-use position located inside thediaphragm opening and a retreating position located outside thediaphragm opening as viewed in the optical axis direction, and a casereceiving the ND filter, wherein the case has a side surface overlappingwith the diaphragm cover member, wherein a convex portion protruding tothe side surface of the diaphragm cover member and receiving the NDfilter at the retreating position is formed on the side surface, andwherein the convex portion is received in the concave portion.